Creating continuous sounds using looping techniques has been around since tape recorders were available commercially. The idea with a looped sound is to play out a sound record over and over again in a continuous loop to produce a sound of indefinite length from a single short sound record. For instance, the sound of a drum as a background beat can be created by having a single drum-hit sound record played over and over. This is useful in musical synthesizers where a selected drum record can be played out in a loop to provide a constant drum beat to set the timing of the music. This eliminates the need to have a entire drum sequence stored in digital memory or the need for the operator to constantly strike a drum key to maintain the beat.
The problem with any looped sound is that it will get quite boring or irritating when listened to for long periods of time. The mind quickly detects a pattern when the same sound is played over and over and starts to expect or anticipate the next loop segment. The effect is for the mind to either try to tune the sound out or to be distracted by it like listening to the sound of dripping faucet.
Sounds in Nature never precisely repeat. Even when a sound appears to be repetitive, there are always slight differences that tell the listener that the sounds are being created new each time. A drum that is hit consistently, sounds a little different each time and each revolution of a motor that seems to be generating a constant sound, has its own variability. It is this variability that is missing in looped sound that clues the listener in to the fact that it is the same sound record repeated over and over and tells tile listener that it is not a realistic sound effect. Most sounds in Nature or sounds made by man-made machines are not truly periodic. There are slight changes in amplitude and phase that make each "apparent period" slightly different in content. For instance, consider the case of man-made motor sounds of a constant running diesel engine. No matter how smooth a motor is running, it can not run perfectly. There are always slight changes in amplitude or misses or RPM changes that make motors sound like motors. It is the combination of randomness and repetitiveness that gives sounds of machines a "real quality". You know what a motor is going to sound like from second to second--but not quite. You don't know if it will "miss" or speed up slightly or whatever. But what you don't expect is for it to sound perfectly the same.
If we make up motor sounds or horns or any so called "repetitive sound" by looping a short sound record, the sound would be too perfect, too exact and too boring to be believable.
Other continuous sounds that are not considered periodic do even worse when played in a continuous loop. For instance, the sound of children playing could be recorded for some finite time (say 10 seconds) and then played back in a continuous loop to model background playground sounds. However, if there are any distinctive sounds, like a child yelling a phrase or something, the listener will quickly recognize the sound record and the effect will become expected. The sound will have lost its innocent quality and will become irritating. The sound of babbling brooks, wood fires, water falls, traffic sounds, sea shore waves, etc. are all continuous non-repeating sounds that are poorly modeled by a repetitive loop.